Milling-cutter.



APPLICATION F 1912. 1,140,130. Patented May 18,1915.

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C. A. DIES. MILLING CUTTER.

APPLICATION FILED DEC. 3|. I9 lZ.

Patented May 18, 1915.

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UNITED STATES PATENT. onnronf CHARLES A. DIES, or nvans'ron, 'ILLINorsAssIeNoB 'IO CLAYTON MARK, or r EVANSTON, rumors.

MILLING-CUTTER.

Specification of Letters Patent.

Patented May 18,1915.

Application filed December 31, 1912. Serial No. 739,436.

To all whom it may concern:

citizen' of the United States, residing at Evanston, in the countyof Cook andStatc' of Illinois, have invented certain new. and

useful Improvements in Milling-Cutters, of

which the following is a specification.

' This invention relates to improvements inmilling cutters, and has for its object to provide an improved millingcutter for use in milling threads.

Hitherto the milling of threads has been 7 attended with considerable difliculty and has had many drawbacks, and it has been found in the use of the ordinary milling cutter that the threads when completed are not smooth, but are rough and unfinished. To

do away with the above-mentioned dililculties and cut a smooth finished thread without cramping of the cutter, and without'un necessary binding and friction, is thefprincipal object of this invention. v

In the accompanying drawings-Figure 1 is a side elevation. of' the cutter; Fig. 2 isan endelevation. ofthe same; Fig. 3 is a longitudinal section "through the cutter;

Fig. 4 is a longitudinal cross section show ing the cutter brokenaway after the completion of the initial cut; and Fig. 5 is av view similar to Fig. 4 after the completion of the final cut.

, Like figures refer to like elements throughout the drawings. This device is designed for use in milling internal or external threads in couplings, pipes, or other work. Hitherto in the milling of threads, the milling cutter has been rotated on its axis at a comparatively high rate of speed while the work is rotated at a comparatively slow rate of speed about its axis, the cutter being located eccentrically with respect to the work and either the cutter or the work moved longitudinally at a rate of speed proportioned to its rotation so as to advance the same a distance equal to the pitch of the thread for one rotation of the work. This device is intended for use in such milling and embodies essential differences which will be brought out in the following description.

The cutter is denoted. generally by the numeral 10, and is formed with a central tapered aperture .11 threaded internally at 12 to engage a spindle 18 or other carrying member, shown in Figs. 4 and 5. The body Be it known that I, CHARLns A. Dms, a

of the cutter is fluted longitudinally, as shown at 13, leaving the projections 14 on the outer peripherythereof. The cutter is so fluted that the projections have their front side or face inclined slightly with respect to planes through the longitudinalaxis of the cutter proper, as will be apparent in Figs. 1 and'2 of the drawings. Thesepro jecting shoulders 14 are thereby formed thicker at their front .ends 15 than the portions 16. at their rear ends, as shown in F ig. L

l of the drawings, for a'purpose to be hereinafter described.

Teeth 17- are on each; shoulder are so out, or otherwise formed' on the projecting membersll, of the size desired and spaced a predeterrnlned distance apart. The teeth} formed, as to form with the corresponding it teeth on the shoulders concentrically 'arranged series planes approximately at rlght angles to the axis of the cutter proper.

These teeth on each shoulder are spaced apart a distance'between their points equal a I to twice the pitch of the, thread to becut by It will be apparent that having the ex.-

"tremity 15 of each shoulder slightly thicker than the extremity 16,.in the manner shown in Figs'l and '2 of the drawings, the concentric series of teeth nearest the extremity 15 will engage the work first, and the engagement of successive teeth along each (sihoulder will be gradual rather than coincient. r i

The operation or use of the cutter is" as follows: The cutter is carried by aspindle or other member 18, as shown in Fig. 4 ofthe drawings, and rotated about its axis at v the desired cutting speed. 19 designates a coupling or pipe in which it is desired to mill an internal thread. This pipe 19 will be rotated about its axis at a selected speed while the spindle 18, carrying the cutter-10, is rotated at the cutting speed about its axis, which will preferably be inclined so as to bring the concentric circles of teeth at the desired angle, that is, planes through the concentric circles of teeth will be approximately parallel with planes through the segments of the threads adjacent the cutting point. The spindle 18 is advanced longitudinally relative to the work 19 at a speed so proportioned to the rotation of the work as to advance the milling cutter a dis tance equal to the pitch of the thread being cut for one revolution of the work; so that at the completion of one rotation of the initial cut, as I have termed it, the pipe 19 will present an appearance similar to that shown in Fig. 4 of the drawings, the cutter being broken away to clarify the showing.

It will be apparent that the thread is incomplete at the completion of the initial out, since the cutting teeth of the milling cutter 10 being spaced between their points a distance equal to the pitch of the thread, the advancement of the milling cutter 10 a distance equal to the pitch of the thread will cause a series of incomplete threads, as shown in Fig. 4. Upon the next revolution of the work, however, the final cut, as I have termed it, is taken, and the thread is completed, as shown in Fig. 5.

By this construction and method of cutting I have found that the use of the ordinary thread milling cutter is obviated and a smooth continuous thread is out.

While I have described a particular method of using this cutter, I do not wish to be confined thereto nor do I wish to be confined to the form or dimensions of the device shown in the drawings beyond the scope of the appended claims.

What I claim is 1. A milling cutter adapted for use in cutting threads, said cutter comprising a body fluted to form longitudinal shoulders on the outer periphery thereof each of said shoulders being provided with a series of cutting teeth and having the forward side thereof inclined relatively to a plane containing the longitudinal axis of said cutter, each of said shoulders having its rear side lying in a plane containing said longitudinal axis. I

2. A. milling cutter comprising a plurality of concentric series of teeth, the teeth of adjacent series lying in rows longitudinally of said cutter, each of said concentric series of teeth being spaced from the adjacent series a distance between their points approximately equal to twice the pitch of the thread to be cut by said cutter.

8. A milling cutter adapted for use in cutting threads, said cutter being tapered toward its front portion, shoulders formed on said cutter, teeth. carried by each of said shoulders, said teeth being arranged in concentric series, each series being spaced from the adjacent series a distance between their points equal to twice the pitch of the thread to be cut.

In testimony whereof, I have subscribed CARL O. BERGMAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

